Indian Journal of Pathology and Oncology 2021;8(4):518–521

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Indian Journal of Pathology and Oncology

Journal homepage: www.ijpo.co.in

Case Report

Mixed mucinous carcinoma of breast – A case report

Mohini Gupta

1,*, Mary Lilly S1, A Josephine1, Vinutha Gali1

1Dept. of Pathology, Sree Balaji Medical College and Hospital, Chromepet, Tamil Nadu, India

A R T I C L E I N F O

Article history:Received 17-08-2021Accepted 14-09-2021Available online 23-11-2021

Keywords:Mucinous carcinomaMixed typeBreast carcinomaNeuroendocrine differentiationCapella type B

A B S T R A C T

In females breast carcinoma is the most common cancer worldwide. Globally, 2.3 million women werediagnosed and 685 000 deaths due to breast cancer were reported in year 2020. Even in the era ofimmunohistochemistry (IHC) and molecular studies, the aggressive nature of the breast cancer can bedetermined by its histological type, grade, nodal status, and metastasis. Mucinous carcinoma (MC) is a rarevariant of invasive breast cancer accounting for 1-7%. It is represented by the presence of large extracellularmucin pools. Based on the mucin content two main subtypes are identified: Pure Mucinous Carcinoma(PMC) and Mixed Mucinous Carcinoma (MMC). Pure Mucinous Carcinoma (PMC) is localized in mostof the cases, whereas the mixed forms tend to metastasize to lymph nodes. Hence the mixed forms oftenrequire an axillary dissection during surgery. We are presenting a case of 70 year old female who presentedwith the complaints of lump in the right breast since 2 months and on ultrasound work up a score ofBIRADS V was given. She underwent right modified mastectomy with right axillary dissection and wasdiagnosed as mixed type of mucinous adenocarcinoma breast by histopathological examination. It wasconfirmed by IHC which showed positivity for ER, PR & Synaptophysin and negativity for Her2neu.Prognostically MC is better compared to other variants of invasive ductal carcinoma as they respond tohormone therapy.

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1. Introduction

Mucinous Carcinoma (MC) approximately accounts for1-7% of breast carcinomas. It is most commonly seenin perimenopausal and postmenopausal women.1,2 PureMucinous Carcinoma (PMC) has a better prognosis ascompared to ductal or lobular variants of breast cancerand Mixed Mucinous Carcinoma (MMC) has unfavourableprognosis with early nodal metastases.3 Hence it isimportant to differentiate between the two variants ofmucinous carcinoma.

* Corresponding author.E-mail address: mohinigupta243@gmail.com (M. Gupta).

2. Case History

We present a case of 70 year old female who came with thecomplaints of lump in the right breast since 2 months withno family history of breast cancer. On clinical examination,an irregular swelling of 2x1 cm was noted in upper outerquadrant and right axilla had a palpable swelling of 1x1cm.Ultrasound showed a well defined heterogenous lesion withfew specks of calcification measuring 2.1x1.4cm at 10-12‘oclock position involving the retroareolar region was seenand a BIRADS V score was given. Fine Needle AspirationCytology (FNAC) examination of breast was done and itwas positive for malignant cells.

The patient underwent Right Modified mastectomy withright axillary dissection. On gross examination, a whitishhard tumour beneath Nipple Areolar Complex measuring

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2x1cm with fibrous area and specks of calcification wasnoted. On Microscopic Examination, Sections from thetumour studied show a neoplasm composed of islandsof tumour cells suspended in extracellular mucin (<30%)separated by thick fibrous septae – Capella Type B.Focal areas showing tumour cells arranged in solid nests.Individual tumour cells are oval with moderate eosinophiliccytoplasm and round to oval vesicular nuclei, mitosis is rare.Ductular formation is scanty. Multiple foci of intraductalcarcinoma, solid type, cribriform type and comedo typesseen. 3/13 lymph nodes were positive and margins were freeof tumour.

Immunohistochemistry was done –ER, PR, Synaptophysin were positive andHer2neu was negative.

Fig. 1: Scanner view showing fatty tissue with islands of tumourcells suspended in extracellular mucin

Fig. 2: Low power view of tumour cells suspended in extracellularmucin

3. Discussion

In our Institution, during last 3 years 50 cases of breastcarcinoma were reported out of which only 3 cases i.e., 6%

Fig. 3: High power view of individual oval tumour cells witheosinophilic cytoplasm and vesicular nuclei

Fig. 4: Low power view of lymph node showing tumour depositssurrounded by perineural fat

Fig. 5: High power view showing positivity for ER

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Fig. 6: High power view showing positivity for PR

Fig. 7: High power view showing positivity for synaptophysin

Fig. 8: High power view showing negativity for Her2neu

were mucinous adenocarcinoma of breast. FNAC was donein this case which was positive for malignancy.

MC is a relatively rare histological subtype that ischaracterized by neoplastic cells that are arranged in sheetsor clusters and are suspended in extracellular mucin. InPMC, mucinous component is >90% consisting of solelyof tumor tissue with extracellular mucin production.1

MMC has 10-90% of mucin along with invasive ductalepithelial component. Based on the cellularity andendocrine differentiation, two types of MC has beensuggested. Capella type A shows scattered small epithelialclusters, strips or cribriform structures floating in poolsof extracellular mucin. Capella type B shows large sheetsof tumor cells with mucin production and neuroendocrinefeatures which was confirmed by Synaptophysin IHC inthis case.4,5 Most of the MC cases are ER, PR Positiveand Her2neu negative. MMC have higher rate of nodalinvolvement.6

It is important to differentiate MC from non-neoplasticmucocele like lesions.7 The absence of cytological atypiain epithelial lining of mucin filled ducts and presence ofmyoepithelial cells in pools of mucin which are extravasatedin stroma due to rupture of cystically dilated mucin filled arefeatures of mucocele like lesions.

4. Conclusion

In view of nodal involvement, it is important to differentiatebetween PMC and MMC. PMC usually shows a betterprognosis and a lower lymph node metastatic rate comparedto MMC.8 Adjuvant endocrine therapy is indicatedfor hormone responsive tumors as most of mucinouscarcinomas are positive for estrogen receptor and/orprogesterone-receptor.7,9

5. Abbreviations

IHC – Immunohistochemistry; MC - Mucinous carcinoma;PMC - Pure Mucinous Carcinoma; MMC - MixedMucinous Carcinoma; FNAC - Fine Needle AspirationCytology; BIRADS - Breast Imaging-Reporting and DataSystem; ER – Estrogen Receptor; PR – ProgesteroneReceptor

6. Source of Funding

None.

7. Conflict of Interest

The authors declare no conflict of interest.

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Author biography

Mohini Gupta, Post Graduate

https://orcid.org/0000-0002-6830-2342

Mary Lilly S, Professor and HOD

A Josephine, Associate Professor

Vinutha Gali, Assistant Professor

Cite this article: Gupta M, Lilly S M, Josephine A, Gali V. Mixedmucinous carcinoma of breast – A case report. Indian J Pathol Oncol2021;8(4):518-521.